LG 42PC55-ZB (CHASSIS:PD73A) Service Manual ▷ View online
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5. In case of strange screen display in specific modes
5-1. In case of no OSD display
(1) Symptom
1) LED is green.
2) The minute discharge is continuously accomplished from the module.
2) The minute discharge is continuously accomplished from the module.
(2) Procedure check
Is the LVDS cable
normal ?
Is the VSC Board
normal?
Is the LVDS cable
connected?
Re-insert the Cable.
Yes
No
No
Yes
Does the FIL8548
IC(IC700) operate?
Replace the FIL8548
IC(IC700)
No
Is the Ctrl Board of
Module normal?
Replace the Ctrl B/D.
No
No
Yes
Replace the VSC B/D
Replace the cable.
Yes
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5-2. In case there is no display on the screen in specific modes
(1) Symptom
1) There is no screen display from a specific input mode
(RF, AV, Component, RGB, DVI).
(2) Procedure check
1) Check the all input modes have normal display.
2) Check the video(main)/ data(sub), video(main)/ video(sub) have normal
2) Check the video(main)/ data(sub), video(main)/ video(sub) have normal
displays from the PIP mode or DW mode(re-check it/ swap).
(3) In case of an unusual display in RF mode
(4) In case of an unusual display in side S-video/ AV mode
Is the Tuner normal?
Is the CXA2069Q normal?
Is the Tuner Cable connected?
Re-insert the cable
Yes
No
No
Yes
Is the FIL8548 normal?
Replace the Tuner.
No
Are the Input voltage, IIC Communication
and CVBS output normal?
Yes
Are the Input voltage, IIC
Communication and HV sync normal?
No
Replace the IC.
No
Are the input voltage, IIC
Communication and HV sync normal?
No
Block A
Replace the IC.
No
Is the Video input of the AV
Jack(P1400) normal?
Yes
Is the CXA2069Q normal?
Check the input source
No
Are the Input voltage, IIC
Communication and HV sync normal?
No
Replace the IC.
No
Yes
Same as Block A
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(5) In case of an unusual display in Component, RGB mode
(6) In case of an unusual display in HDMI mode
(7) In case of an unusual display in SCART1 mode
(8) In case of an unusual display in SCART2 mode
Are the R,G,B input and H,V
Sync of the J1100 normal?
Check the input source
No
Is the HDMI002(IC1004)
normal?
Yes
Same as Block A
Are Input voltage, IIC Communication
and HV sync normal?
No
Is the Video input of the
A/V Jack(J1200) normal?
Yes
Same as Block A
Check the input source
No
Replace the IC.
No
Is the Video input of the
A/V Jack(J1201) normal?
Yes
Same as Block A
Check the input source
No
Yes
Same as Block A
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6. In case of no sound
(1) Symptom
1) LED is Green.
2) Screen display appears but there is no sound.
2) Screen display appears but there is no sound.
(2) Procedure check
All input(modes) have
no sound?
Is there no sound only
for HDMI?
No
Yes
Download
the EDID data
Check the signal after
CAX2069 refer to circuit diagram
No
Is there no sound only
for specific?
(except HDMI,DTV,RF)
Check the signal before
CAX2069 refer to circuit diagram
No
YES
YES
Is there no sound only
for RF?
Check the Tuner IN/OUT
No
YES
YES
Is there no sound only
for AV/component/PC?
Is the output of
CXA2069 normal?
No
YES
Is the IC1300
operating normally?
Replace the IC1300
(MSP4450)
No
Is the IC1301
operating normally?
Replace the IC1300
(STA335BW)
No
YES
Replace the VSC B/D
YES
No
Replace the CXA2069
Is the speaker on?
Set speaker on in the
menu.
No
Is the speaker Cable
normal?
Check the Speaker
Cable.
No
Yes
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